This week I had a tough choice between big and small: Megalopolis, the ambitious, already somewhat notorious science fiction epic from Francis Ford Coppola; and My Old Ass, a Canadian comedy with a cheeky title. I took a rain check on the first and saw the second, partly out of curiosity and partly for its more manageable running time. The second film from writer-director Megan Park, My Old Ass premiered at this year's Sundance Film Festival and is distributed by Amazon MGM Studios. Whether the festival pedigree and limited theatrical release (at the Majestic 10 in Williston and Capitol Showplace in Montpelier as of press time) qualify it as an "indie" these days is anyone's guess. The deal Elliott (Maisy Stella) is a small-town girl who can't wait to escape from her family's cranberry farm to college in Toronto. On her 18th birthday, she celebrates her freedom by hooking up with her childhood crush (Alexandria Rivera) and camping out on an island with her two best friends (Kerrice Brooks and Maddie Ziegler). When they do mushrooms, Elliott's trip takes a weird turn. Suddenly she's face-to-face with her 39-year-old self (Aubrey Plaza), who has advice for her: Be sure to bond with her family before college and avoid a boy named Chad. Elliott blames the shrooms — until the next day, when "My Old Ass" starts calling and texting her. Maybe she should heed her future self's warnings, after all. Spending time with the fam is easy enough. But when she meets a sweet Chad (Percy Hynes White) who happens to have a summer job at her folks' farm, all bets are off. Will you like it? The streaming services are pioneering a new class of movies we might call "ultra-accessible indies," with Apple TV's surprise Best Picture Oscar winner, CODA, as Exhibit A. Despite its supernatural twist, My Old Ass has much in common with that movie: a picturesque setting (this one takes place on an Ontarian lake); coming-of-age themes; an outdoorsy heroine who works with her hands but dreams of a different life; and tastefully low-key sentimentality. Park's film has elements of a stoner comedy, and its title might put off some older viewers. But ultimately it's more heartwarming than irreverent: a movie for teens and their moms to watch together. Just don't come expecting a showcase for Plaza's deadpan talents. She steals every scene she's in,…